The way I see it, Dante has always been a gigantic dork. A Ninja Turtle in every sense of the word, sans shell. That was one of his most endearing qualities, though. It was never really all that "cool." His actions were, but his personality wasn't...it was sorta juvenile. So, seeing a lot of the juvenile vitriol from the people seems logical, when you factor in the people who truly think Dante was "cool" and that DmC is a complete affront to that...it makes sense.
"Cool" is mostly subjective anyway, though...